Transition for three-dimensional, compressible boundary layers
Abstract
The SCOLIC computer code was developed for three dimensional compressible boundary layers on airfoils operating in the transonic regime. The problem of estimating the location of the laminar to turbulent transition is solved using temporal stability theory, and the point of transition is estimated according to an amplification or N-factor criterion. The methodology used in the computer code is described and some results using SCOLIC are presented. Transition predictions obtained with SCOLIC were compared to experimental data for seven different airfoils and it was found that the results were generally satisfactory. Test results for the NAE airfoil series are typically represented by the NAE-80-060. The calculated N-values suggest that the profile design is very effective at suppressing instabilities. Eventually, an instability of frequency 11,456 Hz, with point of inception at about 10 percent chord, does lead to transition around 64 percent chord which agrees remarkably well with experimental observations. For the E-580 NLF airfoil, computed results indicate that instabilities at 162 Hz and 143 Hz lead to transition at about 60 percent chord, while the transition is experimentally observed to occur at 62.6 to 65 percent chord. SCOLIC reproduces the suppression of leading edge instabilities observed with this airfoil.
- Publication:
-
4th CASI Aerodynamics Symposium
- Pub Date:
- 1993
- Bibcode:
- 1993casi.symp...45M
- Keywords:
-
- Boundary Layer Stability;
- Boundary Layer Transition;
- Compressible Boundary Layer;
- Computational Fluid Dynamics;
- Three Dimensional Boundary Layer;
- Transition Points;
- Airfoils;
- Applications Programs (Computers);
- Computerized Simulation;
- Transonic Flow;
- Fluid Mechanics and Heat Transfer